Loss And Loss Adjustment Expense Reserves (Schedule Of Total Estimated Recoveries From Ineligible Second-lien Mortgage Loans) (Details) (Ineligible Mortgage Loans [Member], USD $) In Millions	9 Months Ended
Sep. 30, 2011
Ineligible Mortgage Loans [Member]
Loss And Loss Adjustment Expense Reserves [Line Items]
Total Estimated Recoveries from Ineligible loans as of Beginning Balance	$ 2,517
Accretion of Future Collections	55
Changes in Discount Rates	33
Recoveries (Collections)
Changes in Assumptions	213
Total Estimated Recoveries from Ineligible loans as of Ending Balance	$ 2,818

Carrying amount as of the balance sheet date of amounts expected to be recovered under the terms of insurance contracts.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 17

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.17)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_EstimatedInsuranceRecoveries
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant